Cotransduction of Human mdr-1 and Dihydrofolate Reductase Genes into Murine Hematopoietic Cells / 中国实验血液学杂志

ABSTRACT

Transfer of drug resistance genes into hematopoietic cells is an attractive approach to protect hematopoietic system from the toxic effects by chemotherapeutic agents in cancer patients. In this study, transduction of mdr-1 in combination with dihydrofolate reductase (dhfr) gene was performed, and the expression of exogenous genes and chemoprotection capacity in mouse bone marrow cells were observed. The results showed that approximately 15% of bone marrow cells transfected with the retroviral vector expressed mdr-1 as assayed by flow cytometry. Gene transfer resulted in about 0.9 - 13 fold and 0.5 - 2.6 fold increase in the resistance of CFU-GM to taxol and methotrexate in vitro, respectively (P < 0.05). Moreover, seven months after transplantation to syngeneic mice with mdr-1 and dhfr-transfected bone marrow cells, peripheral blood cells in recipients were still positive for gp170 as evaluated by FACS as well as for mdr-1 and dhfr by PCR amplification. These results indicate that hematopoietic progenitors can be transfected by retrovirus containing mdr-1 and dhfr genes, and that functional drug resistance accompanies their expressions. Furthermore, genetic chimerism might exist in hematopoietic stem cells. In conclusion, transfer and expression of mdr-1 and dhfr genes in bone marrow cells might be applicable in gene therapy research in cancer patients.